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  • 1
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract The aim of this study was to evaluate the effects of Nd:YAG laser treatment on subgingival calculus, cementum and dentine, in vitro at different power settings and durations. The study included 2 experiments. In the 1st experiment, 32 extracted teeth with calculus were divided into 8 laser treatment groups. Each tooth was treated on 2, 3 or 4 sites. In the 2nd experiment. 3 extracted cementum covered teeth and 3 extracted root planed teeth with exposed dentine were selected. 1 surface of each tooth was subjected to 8 different laser treatments. In both experiments, all specimens were assessed using scanning electron microscopy. Micrographs were taken from each treated site at X100 and X750 magnifications. An arbitrary scale (from 0 to 3) was used to score the degree of damage caused by the laser. Generally, the laser caused greater damage on calculus than either cementum or dentine. Linear regression analysis showed that higher total energy input caused a greater mean damage score on calculus (R2= 66%, p〈0.001). 3-way analysis of variance showed that for calculus, the power setting, number of pulses per second and the duration of exposure contributed independently to the mean damage score in an additive way. Cementum specimens were not affected by treatment 1 (50 mJ. 10 pps, 1 s). treatment 2 (50 mJ, 10 pps, 5 s), and treatment 5 (50 mJ, 20 pps, 1 s). Dentine specimens were not affected by treatment 1 (50 mJ, 10 pps, 1 s). The results also showed that there was variability in susceptibility of different teeth and different parts of each tooth which was true for calculus, cementum and dentine.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 7920-7925 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have measured the rate at which recorded signals decay in perpendicular Co78Cr17Ta5 alloys, Co70Cr15Ta5Pt10 alloys, and Pd/Co multilayers. At low write frequencies, the magnetization decay resembles that observed by magnetometry. At high write frequencies, the relative decay rate decreases substantially. This is attributed to a change in the demagnetizing energy associated with high linear densities in perpendicular media. A model for magnetization decay is used to deduce the activation volume, the size distribution, and the barrier to flux reversal which exists for the alloy films. A time scale tε is introduced, over which the decay rate is dominated by the initial condition applied by the write head. The observed decay in the multilayers was much lower (〈0.5%/time decade) than in the alloys (3%–4%/time decade) at all of the spatial frequencies tested. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    European journal of neuroscience 6 (1994), S. 0 
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A new mutant rat strain with movement disorders has arisen spontaneously in a closed colony of Albino–Swiss rats at the Department of Anatomy, Glasgow University. The animals possess a progressive locomotor disorder which is first apparent at around post-natal day 10. We here report that tyrosine hydroxylase immunocytochemistry demonstrates that these mutants have profound depletions in dopaminergic systems in the substantia nigra and corresponding areas of neostriatum.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    European journal of neuroscience 22 (2005), S. 0 
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The AS/AGU rat carries a recessive mutation (agu) in the gene coding for the gamma isoform of protein kinase C. The rat is characterized by disordered locomotion and progressive dysfunction of the nigrostriatal dopaminergic (DA) system. This dysfunction begins with a failure to release DA within the striatum and culminates in cell loss within the substantia nigra pars compacta. The present study examines another midbrain aminergic system with input to the basal ganglia, the serotonergic (5-HT) raphe–striatal system originating in the dorsal raphe nucleus. By 3 months after birth, there is a very substantial reduction in the extracellular levels of 5-HT in the dorsal caudate-putamen of the mutants compared with controls (c. 70%). This is accompanied by a proportional increase in the levels of the 5-HT metabolite 5-hydroxyindole acetic acid (5-HIAA). At a later age, there are reductions in whole tissue 5-HT (and increases in 5-HIAA) in both the striatum and the region containing the dorsal raphe nucleus, as well as numbers of 5-HT-immunoreactive cells in the dorsal raphe nucleus. The median raphe appears to be unaffected. The results are seen in terms of an initial dysfunction in transmitter release leading to cell death, perhaps through the formation of free radicals or neurotoxins.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 10 (1998), S. 0 
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The AS/AGU mutant rat is characterized by a wide staggering gait and a movement disorder of the hindlimbs. Local cerebral glucose utilization in the brain was investigated using the [14C]2-deoxyglucose autoradiographic technique to map any functional alterations in the mutant AS/AGU (agu/agu) compared with Albino Swiss controls (+/+). Locomotor tests were also performed to confirm the phenotypic assignment of the animals. Statistically significant reductions in glucose utilization were apparent in 12 of the 44 regions examined in the AS/AGU animals. The regions showing the most significant differences (P 〈 0.01) from the control AS strain were the substantia nigra pars compacta (–23%) and medial geniculate body (–17%). Statistically significant decreases (P 〈 0.05 and P 〈 0.02) in glucose utilization ranging from –15 to –26% were also displayed in the superior colliculus superficial layer, auditory cortex, ventroposterior nucleus of the thalamus, molecular layer of the hippocampus, dentate gyrus, medial amygdaloid nucleus, median raphe nucleus, subthalamic nucleus, medial preoptic area of the hypothalamus and anterior hypothalamus. In no region studied was the mean value of glucose use in the AS/AGU rat greater than in the control animals. The results of this study complement previous behavioural and neurochemical characterization studies of this mutant, confirm that the disorder involves functional disturbances of the basal ganglia, and demonstrate the involvement of the limbic system and some sensory systems.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 6675-6680 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Comparisons of magnetic anisotropy and switching behavior of CoCr-based alloy and Co/Pd multilayer media were made using a vector vibrating sample magnetometer. Magnetic anisotropy energy was determined from angle-dependent measurements of the transverse magnetization, using a simple approximate expression for transverse moment versus applied field and rotation angle. Switching behavior was deduced from hysteresis and angle-dependent energy-loss measurements. The multilayers were found to switch by curling and domain wall motion, while the Co78Cr17Ta5 and Co70Cr15Ta5Pt10 media were found to switch by nearly coherent (Stoner–Wohlfarth) rotation. Plasma oxidation of the multilayers was found to slightly reduce the amount of coupling, but degraded readback amplitude to a contact recording transducer. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 4449-4455 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Small- and large-angle x-ray scattering from epitaxial Fe(001) on an MgO(001) surface has been measured as a function of film thickness, using grazing incidence x-ray scattering. Small-angle scattering shows that for Fe thicknesses less than 15 monolayers, the Fe is islanded with Fe[110](parallel)MgO[100]. For deposition at 360 °C, the Fe lattice parameter increases toward the MgO surface net spacing with increasing thickness in the 1–10 monolayer coverage regime, and then relaxes back toward the bulk Fe lattice parameter at greater thicknesses. Agglomeration of the islands results in changes in the Fe lattice parameter and in the high-angle peak widths. Prior to agglomeration, the measured in-plane lattice parameter versus thickness is described by a pairwise site interaction between the island and the substrate interface nets. Strain relaxation subsequent to agglomeration is described by continuum elasticity theory. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 1147-1149 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: While electron-based structural probes have been extensively applied to low-pressure film growth techniques such as evaporation, similar studies on sputter deposition have been hindered by the relatively high gas pressure (1–10 mT) inherent to the technique. Because x rays scatter more weakly than electrons the absorption in the ambient is not significant and diffraction from the growing film can be observed if a sufficiently bright source of x rays is used. We have developed a chamber which combines features of an ultrahigh-vacuum sputter-deposition system with the goniometric adjustments and the x-ray windows of a scattering chamber. A description of its design and recent results are presented.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 239 (1972), S. 282-283 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The hamster also differs from other laboratory rodents in its aggressive behaviour. In most laboratory rodents the males are more aggressive than females7'8, but both sexes of the golden hamster fight, and females will readily attack and defeat males. Furthermore, castrated males exhibit increased ...
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Hyperfine interactions 92 (1994), S. 1271-1279 
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Conversion electron Mössbauer spectroscopy (CEMS) and X-ray diffraction (XRD) have been used to investigate the structure of Pt/Fe and Cr/Fe multilayers deposited by magnetron sputtering. The Cr/Fe samples consisted of four samples prepared under Ar sputtering pressures of 1.3, 3.0, 5.0, and 10.0 mT, all with the same multilayer structure of 3.5 nm Cr/2.5 nm Fe, repeated 35 times onto c-Si wafer substrates. The quality of the interfaces between Cr and Fe is clearly degraded with increasing sputter pressure, as seen by changes in the relative intensities of four magnetic subspectra in the CEMS and the gradual appearance of a single-line resonance similar to Fe in solution in Cr. The low-angle XRD superlattice peaks also disappear with increasing sputter pressure, while the high-angle XRD shows a tendency for loss of the preferred (110) texture. Two films of Pt/Fe were deposited epitaxially onto MgO single crystals with bilayer periods of 1.3 nm and 2.6 nm and total thickness of 300 nm each. A transition from fcc-PtFe with near-perpendicular magnetic anisotropy to a bcc-Fe/fcc-PtFe mixture with in-plane magnetic texture is observed by CEMS for the factor of two increase in bilayer period.
    Type of Medium: Electronic Resource
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